Diamonds and eclogites of the Jericho kimberlite (Northern Canada)

Hydrogen isotope compositions in carbonado diamond: constraints on terrestrial formation

“…Wang 1998;Sobolev et al 1999;Taylor and Anand 2004). Further, carbon isotope compositions even lower than the carbonado range have been reported for eclogitic diamonds by Cartigny et al (2004) and De Stefano et al (2009) (Fig. 7).…”

“…7 Stable carbon isotope compositions (in ‰ relative to V-PDB) of eclogitic diamonds (De Stefano et al 2009;Stachel et al 2009), framesites and carbonados (Heaney et al 2005). Carbonado compositions compiled by Heaney et al (2005) are plotted within the light grey field and two outliers as light grey squares (see their Figure 1), whereas data obtained in this study are marked by solid squares related to subduction processes.…”

“…This process has been proposed as a mechanism for eclogitic diamond formation (e.g. Cartigny et al 2004;Taylor and Anand 2004;De Stefano et al 2009), thus, the observations presented in this paper are also compared to characteristics of eclogitic diamonds. The presence of K-feldspar may indicate genetic relationship with eclogitic diamonds as sanidine inclusions have been reported in this suite (e.g.…”

“…Additionally, the carbonado grains have a smooth, glossy surface that has been interpreted as "fusion crust" formed during a bolide impact (Shelkov et al 1997;Kletetschka et al 2000). The arguments for extraterrestrial origin have been weakened by recent observations published in the last several years: osbornite (TiN) has been shown to form in deep subduction environment (Dobrzhinetskaya et al 2007), deformation lamellae have been produced experimentally at mantle P-T conditions in carbonado diamond ), green and yellow CL colours have been encountered in terrestrial diamonds (De Stefano et al 2006), native metals have been described in kimberlite-hosted diamonds (Jacob et al 2004 and references therein), diamonds with very low carbon isotope compositions (down to -41‰ relative to V-PDB, Cartigny et al 2004;Cartigny 2007Cartigny , 2008De Stefano et al 2009), low aggregation states (Cartigny 2007(Cartigny , 2008Kagi and Fukura 2008) and elevated hydrogen contents (Hayman et al 2005) have been reported from various types of mantle-derived diamonds. The latter observation is important as the hydrogen content of the carbonado diamond can provide new means to investigate its origin.…”

In situ analysis of garnet inclusion in diamond using single-crystal X-ray diffraction and X-ray micro-tomography

“…Uncertainties are higher than for a conventional electron microprobe analysis, but sufficiently small for a precise classification of the garnet and thus broad petrological purposes, without having to destroy the inclusion as would be required by conventional chemical analysis. The estimated composition is typical of a low-Cr eclogitic garnet and lies within the field of the most common garnet inclusions in diamonds from the Jericho kimberlite (''eclogitic'' 90 %, ''websteritic'' 7 %, ''peridotitic'' 3 %;De Stefano et al, 2009). The use of a complementary technique such as Xray computed micro-tomography, allowed us not only to determine the size of both inclusion and diamond, as well as the exact position of the inclusion in the diamond, but also to find several smaller inclusions, which were not detected by optical examination.…”